well, i would freehand it if it were me, but it will take a steady hand, some really thin paint, a double action airbrush, low airpressure, and plenty of patience. if you wanted to mask it, you could paint the color of the squiggly lines first, then, mask it off by rolling up some poster putty or elmer's tak (found at walmart in the office supply section). cut off a small amount and just roll it up into some very small strings, cut a section of the string off, and attach them to the subject in various shapes and sizes, then spray the desert yellow color on. good luck. later.